Device and method for package warp compensation in an integrated heat spreader

ABSTRACT

A device and method for designing and manufacturing an integrated heat spreader so that the integrated heat spreader will have a flat surface on which to mount a heat sink after being assembled into a package and exposed to the heat of a die. This device and method for designing and manufacturing an integrated heat spreader would generate a heat spreader that would be built compensate for deformations resulting from (1) physical manipulation during assembly (2) thermal gradients during operation and (3) differing rates of expansion and contraction of the package materials coupled with multiple package assembly steps at elevated temperatures so that one surface of the integrated heat spreader would have a flat shape.

FIELD

[0001] The invention relates to a device and method for package warpcompensation in an integrated heat spreader. More particularly, thepresent invention is a device and method that determines the warpage inan integrated heat spreader (IHS) and compensates for this warpage toimprove the heat dissipating properties of the IHS.

BACKGROUND

[0002] In the rapid development of computers many advancements have beenseen in the areas of processor speed, throughput, communications, faulttolerance and size of individual components. Today's microprocessors,memory and other chips have become faster and smaller. However, with theincrease in speed, reduction in the size of components, and increaseddensity of circuitry found within a given chip/die, heat generation anddissipation have become a more critical factor than ever.

[0003] To facilitate the dissipation of the heat generated by a die, anIHS may be affixed to the die and maybe used in conjunction with a heatsink. The IHS is affixed to the die with a layer of thermal interfacematerial that is used to provide some adhesion between the IHS and thedie and transfer heat from the die to the IHS. In addition, a heat sinkmay be placed on top of the IHS with a layer of a thermal interfacematerial placed between the IHS and heat sink to facilitate a limitedamount of adhesion and transfer heat from the IHS to the heat sink. Theheat sink may have vertical fans extending there from to increase thesurface area of the heat sink and facilitate the transfer heat from theIHS to the ambient air. As would be appreciated by one of ordinary skillin the art these heat sinks may take many different forms and mayinclude a small electric fan.

[0004] A package may be formed during the assembly process by affixingthe die to a substrate and then placing the IHS on top of the die andthe heat sink on top of the IHS. The placement of the IHS on top of thedie may be accomplished utilizing an industrial robot arm with agrasping tool affixed to the robot arm. The grasping tool may hold theIHS at the edges thereof and place it on top of the die.

[0005] Since the die may be made flat and rectangular or square inshape, the IHS is also designed to be flat so that the thermal interfacematerial between the die and the IHS and the thermal interface materialbetween the IHS and heat sink is of a uniform thickness to dissipateheat throughout the die to the IHS and thereafter to the heat sink.

[0006] However, because the assembled package contains materials withdifferent coefficients of thermal expansion, and because the package isassembled in steps at various temperatures and because temperaturegradients exist in a “powered-up” package the IHS will deform so that itno longer remains flat. Once this deformation occurs in the IHS, thethickness of the thermal interface material between the heat sink andthe IHS would vary and the IHS would no longer be able to uniformlydissipate heat from the die to the heat sink.

[0007] Further, even though a die may be relatively small, the heatgenerated by a die may not be evenly distributed throughout the die. Inother words, hotspots may be seen in relatively small locations of a diewhere power consumption is high or heat generating circuits are present.

[0008] Therefore, what is needed is a device and method that candetermine the manner in which an IHS will deform due to either or bothphysical manipulation of the IHS itself and heat fluctuations caused bypowering on and off the die in the package. Further, this device andmethod should compensate for the warpage seen in the IHS so that thedistance between the IHS and heat sink remain approximately constant.Still further, this device and method should compensate for hotspots ona die and provide additional heat dissipating material in an IHS.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The foregoing and a better understanding of the present inventionwill become apparent from the following detailed description ofexemplary embodiments and the claims when read in connection with theaccompanying drawings, all forming a part of the disclosure of thisinvention. While the foregoing and following written and illustrateddisclosure focuses on disclosing example embodiments of the invention,it should be clearly understood that the same is by way of illustrationand example only and the invention is not limited thereto. The spiritand scope of the present invention are limited only by the terms of theappended claims.

[0010] The following represents brief descriptions of the drawings,wherein:

[0011]FIG. 1 is an example of a package prior to assembly in an exampleembodiment of the present invention;

[0012]FIG. 2 is an example of an assembled package with the IHS 10having deformed by bowing out in the center due to differences inpackage material coefficients of thermal expansion or to physicalmanipulation and/or temperature gradients in an example embodiment ofthe present invention;

[0013]FIG. 3 is an example of an assembled package with the IHS 10having deformed by bowing in the center due to differences in packagematerials coefficients of thermal expansion or to physical manipulationand/or temperature gradients in an example embodiment of the presentinvention;

[0014]FIG. 4A is an example of a Morié Fringe image of a free-standingIHS 10 as supplied by a manufacturer in an example embodiment of thepresent invention;

[0015]FIG. 4B is an example of a Morié Fringe image of an IHS 10 at roomtemperature after being attached to the substrate in an exampleembodiment of the present invention;

[0016]FIG. 4C is an example of a Morié Fringe image of an IHS 10assembled into a package, where the entire package is being soaked at 90degrees Celsius in an example embodiment of the present invention;

[0017]FIG. 5A is an example of an IHS 10 having a shape designed tocompensate for the curvature seen in FIGS. 2, 4A, 4B and 4C in anexample embodiment of the present invention;

[0018]FIG. 5B is an example of an IHS 10 having a shape designed tocompensate for the curvature seen in FIG. 3 in an example embodiment ofthe present invention;

[0019]FIG. 6 is an example of an assembled package in which the IHS 10has been processed utilizing the compensated IHS 10 shown in FIG. 5A or5B and the logic shown in either FIG. 7 or FIG. 8 in an exampleembodiment of the present invention;

[0020]FIG. 7 is an example of an assembled package in which the IHS 10has been processed utilizing the compensated IHS 10 shown in FIG. 5A or5B and the logic shown in either FIG. 7 or FIG. 8 taking intoconsideration a hotspot on die 50 in an example embodiment of thepresent invention;

[0021]FIG. 8 is an example of the process of used to generate the IHS 10shown in FIGS. 5A and 5B resulting in the IHS 10 shown in FIGS. 6 and 7in an example embodiment of the present invention; and

[0022]FIG. 9 is an example of the process of used to generate the IHS 10shown in FIGS. 5A and 5B resulting in the IHS 10 shown in FIGS. 6 and 7in an example embodiment of the present invention.

DETAILED DESCRIPTION

[0023] Before beginning a detailed description of the subject invention,mention of the following is in order. When appropriate, like referencenumerals and characters may be used to designate identical,corresponding or similar components in differing figure drawings.Further, in the detailed description to follow, exemplarysizes/models/values/ranges may be given, although the present inventionis not limited to the same. As a final note, well-known components ofcomputer networks may not be shown within the FIGs. for simplicity ofillustration and discussion, and so as not to obscure the invention.

[0024]FIG. 1 is an example of a package prior to assembly in an exampleembodiment of the present invention. FIG. 1 illustrates a package havinga die 50 attached to a substrate 30 using epoxy 60 with a finite amountof a thermal interface material (TIM) 20 placed on top of the die 50.This TIM 20 serves at least two primary purposes. First, it acts toconduct heat from the die to the integrated heat spreader (IHS) 10.Second, it also provides some adhesion between the IHS 10 and die 50.During the manufacturing process the IHS 10 is pressed down upon the TIM20 and adhesive 40. Thereafter, thermal interface material (TIM) 80would be placed on IHS 10 with the heat sink 70 placed on top of IHS 10.TIM 80 servers the same function as TIM 20 and may be composed of thesame material. Throughout the foregoing discussion the term package willrefer to the combination of, but not limited to, the substrate 30, epoxy60, die 50, thermal interface material 20, IHS 10, thermal interfacematerial 80, heat sink 70 and adhesive 40.

[0025]FIG. 2 is an example of an assembled package with the IHS 10deformed by bowing out in the center due to physical manipulation and/ortemperature fluctuations in an example embodiment of the presentinvention. As shown in FIG. 2, the IHS 10 would absorb heat from die 50through TIM 20 and be held in place on the substrate 30 via adhesive 40.On top of the IHS 10 a heat sink 70 or fan/heat sink combination (notshown) would be mounted to dissipate the heat absorbed by the IHS 10.However, since IHS 10 and TIM 20 both experience significant stressesduring the assembly process and due to (1) physical manipulation andapplied stresses during package assembly and (2) thermal expansion andcontraction when the die is powered on and off, and (3) differences inmaterial coefficients of thermal expansion, the IHS 10 may change itsshape. As indicated in FIG. 2, the IHS 10 has bowed outward in thecenter so that TIM 80 is thicker in the center between heat sink 70 andIHS 10 as opposed to the outer edges. As previously discussed die 50 isconnected to substrate 30 via epoxy 60. IHS 10 is affixed to substrate30 via adhesive 40. Further, die 50 is connected to IHS 10 via TIM 20.

[0026]FIG. 3 is an example of an assembled package with the IHS 10having deformed by bowing in the center due to physical manipulationand/or temperature fluctuations or differences in material coefficientsof thermal expansion in an example embodiment of the present invention.The sole difference between FIG. 2 and FIG. 3 is the nature of thedeformation of the IHS 10. As would be appreciated by one of ordinaryskill in the art how the IHS 10 may be deformed is dependent on thematerials it is made of, the manner of handling, and the heat it isexposed to by die 50. Therefore, FIGS. 2 and 3 are provided merely asexamples of how and IHS 10 may deform. Regarding the heating of the IHS10 this is dependent upon how die 50 generates and dissipates heat. Forexample, die 50 may generate heat at a specific location such as thecenter of the die 50 or it may dissipate heat at the outer edges of thedie 50. The manner in which die 50 dissipates heat would directly affectthe deformation seen in the IHS 10. Since all other elements shown inFIG. 3 remain the same as that shown in FIG. 2, no further discussion ofthese elements will be provided here.

[0027]FIG. 4A is an example of a Morié Fringe illustration of an IHS 10as supplied by a manufacturer without being attached to a substrate 30in an example embodiment of the present invention. It should be notedthat the sensitivity of the Morié Fringe illustration is 12.5 micronsper fringe and that FIG. 4A is a top view of IHS 10. As indicated inFIG. 4A, as received from the manufacturer the IHS 10 is effectivelyflat.

[0028]FIG. 4B is an example of a Morié Fringe illustration of an IHS 10after being at room temperature as assembled into a package in anexample embodiment of the present invention. As with FIG. 4A, it shouldbe noted that the sensitivity of the Morié Fringe illustration is 12.5microns per fringe and that FIG. 4B is a top view of IHS 10. Asindicated in FIG. 4B, after attachment to substrate 30 and at roomtemperature the IHS 10 significantly deformed as compared to thatreceived from the manufacturer of the IHS 10. Since assembly occurs atroom temperature, but curing of the sealant occurs at elevatedtemperatures, the entire package will warp when cooled to roomtemperature as seen in FIG. 4B. This can affect the adhesion between theheat sink 70 and the IHS 10 using the thermal interface material 80, asshown in FIG. 2. Further, it would affect the thickness of the thermalinterface material 80 and thereby the heat dissipation capabilities ofthe heat sink 70. In FIG. 4B a substrate is attached to the IHS,however, it is not visible in the picture.

[0029]FIG. 4C is an example of a Morié Fringe illustration of an IHS 10in an assembled package, where the package is being exposed to a 90degree Celsius heat soak after attachment to substrate 30 (not shown) inan example embodiment of the present invention. As previously mentionedregarding FIGS. 4A and 4B, it should be noted that the sensitivity ofthe Morié Fringe illustration is 12.5 microns per fringe and that FIG.4c is a top view of IHS 10. As indicated in FIG. 4C, as the temperatureof the entire package is increased to 90 degree Celsius, the IHS 10actually flattens slightly as compared to that shown in FIG. 4B that isat room temperature. However, there is still significant deformationinvolved in the IHS 10 shown in FIG. 4C to the point where two smallbumps are formed in the IHS 10.

[0030]FIGS. 4A through 4C are provided merely as examples of the type ofdeformation that may be seen in an IHS 10. As would be appreciated byone of ordinary skill in the art, the type of deformation that would beseen in the IHS 10 would depend upon the type of manipulation receivedduring assembly, the materials the IHS 10 and the other packagecomponents are composed of, the temperature range the IHS 10 is exposedto, etc. Therefore, in designing the IHS 10 to compensate for anydeformation seen it is necessary to provide a process and method thatcan handle any deformation possible. Further, as would be appreciated byone of ordinary skill in the art, a Morié Fringe analysis is only onemethod of many for measuring deformation is in the IHS 10. Otherexamples would include utilizing laser or even a touch probe to measurethe deformation. All these methods of measuring the shape of the IHS 10will collectively be referred to as a dimensional analysis from thispoint forward.

[0031]FIG. 5A is an example of an IHS 10 having a shape to compensatefor the curvature seen in FIGS. 2, 4A, 4B and 4C in an exampleembodiment of the present invention. The convex shape of the IHS 10illustrated in FIG. 5A is depressed in the middle of the IHS 10. Thisconvex shape would be supplied by the manufacturer of the IHS 10 andwould compensate for the deformation seen in FIG. 2 and FIGS. 4A through4C. As would be appreciated by one of the ordinary skill in the art, theprecise curvature of the IHS 10 would depend upon the nature of thedeformation seen.

[0032]FIG. 5B is an example of an IHS 10 having a shape to compensatefor the curvature seen in FIG. 3 in an example embodiment of the presentinvention. The IHS 10, shown in FIG. 5B, is provided by the manufacturerto compensate for the deformation seen in FIG. 3. In this case, thecenter of the IHS 10 is bowed outward. As would be appreciated by one ofthe ordinary skill in the art, the precise curvature of the IHS 10 woulddepend upon the nature of the deformation seen.

[0033] The IHS 10 illustrated in FIG. 5A and FIG. 5B are provided asmerely examples of ways to compensate for deformations in an IHS 10.Depending upon the deformation involved any number of differentcompensating shapes may be provided. However, it should be noted thatthe compensation provided in the IHS 10 should be opposite to that seenwhen the IHS 10 is mounted and is operating at the die temperature. Thegoal should be for the compensated IHS 10 to be flat as will bediscussed further in reference to FIG. 6.

[0034]FIG. 6 is an example of an assembled package in which the IHS 10has been processed utilizing the compensated IHS 10 shown in FIG. 5A or5B and the logic shown in either FIG. 7 or FIG. 8 in an exampleembodiment of the present invention. It should be noted that the packageillustrated in FIG. 6 is identical to the packages shown in FIGS. 2 and3 with the exception that the IHS 10 is flat and the thermal interfacematerial 80 is of a constant thickness between the IHS 10 and the heatsink 70. Therefore, using the IHS 10 as shown in either FIG. 5A or FIG.5B it is possible once the IHS 10 is grasped by the robot tool andmounted onto die 50 and substrate 30 for it to take on a flat shape oncethe die 50 has obtained its operating temperature. The remainingelements shown in FIG. 6 remain unchanged from those previouslydiscussed in FIGS. 1 through 3 and will not be discussed further here.

[0035]FIG. 7 is an example of an assembled package in which the IHS 10has been processed utilizing the compensated IHS 10 shown in FIG. 5A or5B and the logic shown in either FIG. 7 or FIG. 8 taking intoconsideration a hotspot on die 50 in an example embodiment of thepresent invention. The package shown in FIG. 7 is identical to thatshown in FIG. 6 with the exception that additional material 90 has beenadded to the IHS 10 in order to facilitate the transmission of the heatfrom a specific location on die 50 to heat sink 70. This specificlocation on die 50 is referred to as a hotspot since it generates moreheat than other portions over the die 50. As would be appreciated by oneof ordinary skill the art, certain areas of the die 50 would generatemore heat than others due to the nature of the circuitry at thatlocation. By increasing the thickness of the IHS 10 at that hotspot, itwould be possible to increase the heat transfer capacity of the IHS 10at that location since the distance between the IHS 10 and heat sink 70would be reduced. Of course, the reverse is also possible and the IHS 10may be made thinner at selected points.

[0036] Before proceeding into a detailed discussion of the logic used bythe embodiments of the present invention it should be mentioned that theflowcharts shown in FIGS. 8 and 9 may contain software, firmware,hardware, processes or operations that correspond, for example, to code,sections of code, instructions, commands, objects, hardware or the like,of a computer program that is embodied, for example, on a storage mediumsuch as floppy disk, CD Rom, EP Rom, RAM, hard disk, etc. Further, thecomputer program can be written in any language such as, but not limitedto, for example C++.

[0037]FIG. 8 is an example of the process used to generate the IHS 10shown in FIGS. 5A and 5B resulting in the IHS 10 shown in FIGS. 6 and 7in an example embodiment of the present invention. Processing begins inoperation 800 and immediately proceeds to operation 810. In operation810 a series of packages are built which include IHS 10 elements thatare flat in the as received condition from the supplier. Thereafter, inoperation 820 the packages are heat soaked or elevated to an approximatetemperature at which the die 50 is anticipated to operate at. Inoperation 830, a dimensional analysis is performed on the IHS 10 in eachpackage. This die dimensional analysis may comprising using a MoriéFringe analysis or some other technique for measuring the deformation inthe IHS 10 in each package. As part of the analysis performed inoperation 830 a statistical analysis is performed on the results of thedimensional analysis received for each IHS 10. In this manner an averagedeformation for each IHS 10 can be determined. Thereafter, processingproceeds to operation 840 where a series of sets of IHS 1 O's is aregenerated that have a slightly varying curvature to compensate for thewarpage seen by the die dimensional analysis performed in operation 830.Each set of IHS 10's would comprise a statistically significant numberof IHS 10's that would be of consistent shape with one another within aset, but would very in degree of compensation from one set to another.In this manner it would be possible to select the degree of compensationthat best corrects the warpage seen. However, as would be appreciated byone of ordinary skill in the art, alternatively a simple series of IHS10's may be manufactured and installed in packages. This simple seriesof IHS 10's may simply vary in the degree of compensation or curvatureto form an equal distribution of IHS 10's of varying curvatures. Inoperation 845 the IHS 10 is are assembled into packages which compriseall the elements shown in FIGS. 1 through 3.

[0038] Still referring to FIG. 8, processing then proceeds to operation850 in which the set of packages or package that has the flattestpackage when powered on is selected as the template for the IHS 10design. Thereafter, in operation 860 it is determined if die 50 has anyhotspots therein. In the preferred embodiment operation 860 may beperformed on the assembled package with the heat sink 70 attached. Inthis way the correct stress and thermal conditions seen in actual useare achieved. In a preferred embodiment the hotspots are determined bytemperature sensors contained with in the die 50 itself. In operation870 for any hotspots found in die 50, the curvature of the IHS ismodified in the area of the hotspot to eliminate it. Thereafter,processing proceeds to operation 880 where the IHS 10 with thecompensated shape for warpage and hotspots is manufactured. Processingthen proceeds to operation 890 were processing terminates.

[0039]FIG. 9 is an example of the process used to generate the IHS 10shown in FIGS. 5A and 5B resulting in the IHS 10 shown in FIGS. 6 and 7in an example embodiment of the present invention. Processing beginsexecution in operation 900 and immediately proceeds to operation 910. Inoperation 910, a finite element model is generated for the entirepackage including the IHS 10. Finite element models comprise dividing astructure into a fixed number of smaller pieces or elements andinputting each element and its respective coordinates and relationshipsto other elements into a computer system. In addition, the properties ofeach element, such as, but not limited to, temperature expansioncoefficients, elasticity, heat transfer capability, modulus ofelasticity tensile strength, etc. are entered into the finite elementmodel. Processing then proceeds to operation 920 where the pressurepoints generated by the factory handling equipment, such as, but notlimited to, a robot arm and grasping device, are entered into the finiteelement model. These pressure points would comprise the amount ofpressure being placed on specific elements in the finite element model.The pressure experience by these specific elements would be transferredto other elements contained within the model.

[0040] Still referring to FIG. 9, in operation 930 expansioncoefficients and mechanical properties of each element of the packageare also entered into the finite element model. In operation 940 theoperating temperature of the die 50 is determined and which elements inthe finite element model are affected by the temperature increase of thedie 50. For example, the epoxy 60 would have a different expansioncoefficient than the IHS 10, or the heat sink 70. Processing thenproceeds to operation 950 where the hotspots, if any, in the die 50 areidentified and the corresponding elements in the IHS 10 are alsodetermined. In operation 960 a finite element model is executed and thewarpage of the IHS 10 is determined from the finite element model.Thereafter, in operation 970 the IHS 10 is redesigned to compensate forthe warpage seen in operation 960. In operation 980 the finite elementmodel is executed again with the exception that the IHS 10 compensatedfor the warpage seen earlier is utilized in the model. This would entailreplacing the elements of the IHS 10 that are changed with new elementsof possibly different shape an existing in different positions.Thereafter, in operation 990 it is determined if any warpage can be seenutilizing the compensated IHS 10 in the finite element model. If thewarpage is not eliminated in the finite element model then processingreturns to operation 970 where it is repeated. However, if the warpageis eliminated in the finite element model in operation 980, thenprocessing proceeds from operation 990 to operation 1000. In operation1000 a series of sets of IHS 10's is are generated that have a slightlyvarying curvature to the IHS 10 determined by the finite element model.Each set of IHS 10's would comprise a statistically significant numberof IHS 10's that would be of consistent shape with one another within aset, but would very in degree of compensation from one set to another.In this manner it would be possible to select the degree of compensationthat best corrects the warpage actually seen as opposed to thatpredicted by the finite element model. As would be appreciated one ofordinary skill in the art, no matter how well the finite element modelis generated it still may not behave precisely as predicted in actualoperation. Still further, as would be appreciated by one of ordinaryskill in the art, alternatively a simple series of IHS 10's may bemanufactured and installed in packages. This simple series of IHS 10'smay simply vary in the degree of compensation or curvature to form anequal distribution of IHS 10's of varying curvatures was the IHS 10generated by the finite element model being the medium IHS 10. Inoperation 1010 the IHS 10 is are assembled into packages that compriseall the elements shown in FIGS. 1 through 3.

[0041] Still referring to FIG. 9, processing then proceeds to operation1030 in which the set of packages or package that has the flattestpackage when powered on is selected as the template for the IHS 10design. Thereafter, in operation 1040 it is determined if die 50 has anyhotspots therein. In the preferred embodiment operation 860 may beperformed on the assembled package with the heat sink 70 attached. Inthis way the correct stress and thermal conditions seen in actual useare achieved. In a preferred embodiment the hotspots are determined bytemperature sensors contained with in the die 50 itself. In operation1050 for any hotspots found in die 50, the curvature of the IHS ismodified in the area of the hotspot to eliminate it. Thereafter,processing proceeds to operation 1060 where the IHS 10 with thecompensated shape for warpage and hotspots is manufactured. Processingthen proceeds to operation 1070 were processing terminates.

[0042] The benefits resulting from the present invention is that an IHS10 may be designed that will create and approximately flat package evenafter manipulation and exposure to fluctuations in temperature. Withsuch a near flat package it is possible to effectively and uniformlydissipate heat from a die. In addition, is possible to increase the heatdissipation capacity of the IHS 10 for specific locations associatedwith hotspots in a die 50.

[0043] While we have shown and described only a few examples herein, itis understood that numerous changes and modifications as known to thoseskilled in the art could be made to the example embodiment of thepresent invention. Therefore, we do not wish to be limited to thedetails shown and described herein, but intend to cover all such changesand modifications as are encompassed by the scope of the appendedclaims.

We claim:
 1. A method of manufacturing an integrated heat spreader,comprising: exposing a plurality of integrated heat spreaders to heat;performing a dimensional analysis on each of the plurality of integratedheat spreaders to determine any deformation of a shape of the integratedheat spreader; altering the shape of the plurality of integrated heatspreaders to minimize for the deformation in the shape of the pluralityof heat spreaders as determined by the dimensional analysis.
 2. Themethod recited in claim 1, wherein exposing a plurality of integratedheat spreaders to a heat further comprises: building the plurality ofintegrated heat spreaders so that they have at least one flat surfacearea upon which a heat sink may be placed.
 3. The method recited inclaim 2, wherein building the plurality of integrated heat spreaders sothat they have at least one flat surface area upon which a heat sink maybe placed further comprises: building a plurality of series of theplurality of integrated heat spreaders wherein a series of the pluralityof series comprises at least one integrated heat spreader having a shapeto compensate for deformations seen by the dimensional analysis which isdifferent from a shape of an integrated heat spreader from anotherseries of the plurality of series.
 4. The method recited in claim 3,wherein altering the shape of the plurality of integrated heat spreadersto compensate for any deformation in the shape of the plurality of heatspreaders seen by the dimensional analysis further comprises: selectingthe series of the plurality of series of the plurality of integratedheat spreaders having the at least one surface area remains flat whenexposed to the heat generated by a die.
 5. The method recited in claim4, further comprising: determining if any hotspots are generated by thedie; and modifying a local shape of the plurality of integrated heatspreaders to reduce a gap between the integrated heat spreader and theheat sink.
 6. A method of manufacturing an integrated heat spreader,comprising: generating a finite element model of a package having asubstrate connected to a die connected to the integrated heat spreaderconnected to a heat sink; executing the finite element model to generatethe integrated heat spreader with a shape having deformations; alteringthe shape of the integrated heat spreader to compensate for thedeformations; executing the finite element model using the integratedheat spreader having an altered shape to compensate for thedeformations; and repeating the altering of the shape of the integratedheat spreader to compensate for the deformations and execution of thefinite element model until no further deformations exist.
 7. The methodrecited in claim 6, wherein the generating a finite element model of apackage further comprises: dividing the substrate, the die, theintegrated heat spreader, and the heat sink into a plurality of elementshaving a certain spatial coordinate and connected to other elements ofthe plurality of elements.
 8. The method recited in claim 7, furthercomprising: associating properties with the each of the elements of theplurality of elements, wherein the properties comprise mechanical andthermal properties, wherein thermal properties comprise coefficients ofthermal expansion.
 9. The method recited in claim 8, wherein thedeformations are due to the physical manipulation of the integrated heatspreader or heat absorption by the integrated heat spreader generated bythe die.
 10. The method recited in claim 9, further comprising:identifying hotspots on the die; determining an associated elements onthe integrated heat spreader for the hotspots on the die; and modifyingthe heat spreader geometry to decrease local thermal resistance in theassociated elements on the integrated heat spreader.
 11. A computerprogram embodied on a computer readable medium and executable by acomputer for manufacturing an integrated heat spreader, comprising:exposing a plurality of integrated heat spreaders to a elevatedtemperature; performing a dimensional analysis on each of the pluralityof integrated heat spreaders to determine a shape of the integrated heatspreader; altering the shape of the plurality of integrated heatspreaders to compensate for any deformation in the shape of theplurality of heat spreaders seen by the dimensional analysis.
 12. Thecomputer program recited in claim 11, wherein exposing a plurality ofintegrated heat spreaders to a elevated temperatures further comprises:building the plurality of integrated heat spreaders so that they have atleast one flat surface area upon which a heat sink may be placed. 13.The computer program recited in claim 12, wherein building the pluralityof integrated heat spreaders so that they have at least one flat surfacearea upon which a heat sink may be placed further comprises: building aplurality of series of the plurality of integrated heat spreaderswherein a series of the plurality of series comprises at least oneintegrated heat spreader having a shape to compensate for deformationsseen by the dimensional analysis which is different from a shape of anintegrated heat spreader from another series of the plurality of series.14. The computer program recited in claim 13, wherein altering the shapeof the plurality of integrated heat spreaders to compensate for anydeformation in the shape of the plurality of heat spreaders seen by thedimensional analysis further comprises: selecting the series of theplurality of series of the plurality of integrated heat spreaders havingthe at least one surface area remains flat when exposed to the heatgenerated by a die.
 15. The computer program recited in claim 14,further comprising: determining if any hotspots are generated by thedie; and modifying the local geometry of the integrated heat spreadersto reduce a gap between the integrated heat spreader and the heat sink.16. A computer program embodied on a computer readable medium andexecutable by a computer for manufacturing an integrated heat spreader,comprising: generating a finite element model of a package having asubstrate connected to a die connected to the integrated heat spreaderconnected to a heat sink; executing the finite element model to generatethe integrated heat spreader with a shape having deformations; alteringthe shape of the integrated heat spreader to compensate for thedeformations; executing the finite element model using the integratedheat spreader having an altered shape to compensate for thedeformations; and repeating the altering of the shape of the integratedheat spreader to compensate for the deformations and execution of thefinite element model until no further deformations exist.
 17. Thecomputer program recited in claim 16, wherein the generating a finiteelement model of a package further comprises: dividing the substrate,the die, the integrated heat spreader, and the heat sink into aplurality of elements having a certain spatial coordinate and connectedto other elements of the plurality of elements.
 18. The computer programrecited in claim 17, further comprising: associating properties with theeach of the elements of the plurality of elements, wherein theproperties comprise coefficients of thermal expansion.
 19. The computerprogram recited in claim 18, wherein the deformations are due to (a) thephysical manipulation of the integrated heat spreader (b) heatabsorption by the integrated heat spreader generated by the die (c) nonisothermal processing conditions for the package, coupled with differingcoefficients of thermal expansion for the package materials.
 20. Thecomputer program recited in claim 19, further comprising: identifyinghotspots on the die; determining an associated elements on theintegrated heat spreader for the hotspots on the die; and modifying thelocal geometry of the associative elements on the integrated heatspreader in order to reduce local thermal resistance.
 21. A package,comprising: a die that generates heat; and an integrated heat spreaderconnected to the die to absorb the heat generated by the die and changethe shape of at least one surface of the integrated heat spreader,wherein the at least one surface of the integrated heat spreader becomesapproximately flat.
 22. The package recited in claim 21, furthercomprising: a heat sink connected to the at least one surface of theintegrated heat spreader that is approximately flat to dissipate heatfrom the integrated heat spreader to ambient air.
 23. The packagerecited in claim 22, wherein the at least one surface of the integratedheat spreader connected to the heat sink only becomes flat whenabsorbing heat.
 24. The package recited in claim 22, wherein the atleast one surface of the integrated heat spreader connected to the heatsink only becomes flat when either absorbing heat or grasped formounting.
 25. The package recited in claim 22, wherein the at least onesurface of the integrated heat spreader connected to the heat sink isthicker at points closely associated with hotspots on the die.